[R] Selectively Removing objects

[Paulo Grahl]

Dear list members,

Does anyone know how to use rm() to remove only variables but not
declared functions from the environment ?
I understand I could name all the functions with, let's say
"f_something", make sure that all variables do not start with "f_" and
then remove all BUT objects starting with "f_".
However, I have already defined all the functions and it would be
troublesome to change all of them to a new name.

Any hint ?
Thanks

Paulo Gustavo Grahl, CFA

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[Ben Bolker]

Paulo Grahl <pgrahl <at> gmail.com> writes:

>
> Dear list members,
>
> Does anyone know how to use rm() to remove only variables but not
> declared functions from the environment ?
> I understand I could name all the functions with, let's say
> "f_something", make sure that all variables do not start with "f_" and
> then remove all BUT objects starting with "f_".
> However, I have already defined all the functions and it would be
> troublesome to change all of them to a new name.
>

> a <- 1
> b <- 2
> d <- function(x) { x^2 }
> objs <- ls()
> objclasses <- sapply(objs,function(x) class(get(x)))
> objclasses
a b d
"numeric" "numeric" "function"
> rm(list=objs[objclasses!="function"])
> ls()
[1] "d" "objclasses" "objs"
>

(objclasses and objs are left over, but
a and b have been deleted)

[Gustaf Rydevik]

On Mon, Feb 2, 2009 at 2:16 PM, Paulo Grahl <pgr...@gmail.com> wrote:
> Dear list members,
>
> Does anyone know how to use rm() to remove only variables but not
> declared functions from the environment ?
> I understand I could name all the functions with, let's say
> "f_something", make sure that all variables do not start with "f_" and
> then remove all BUT objects starting with "f_".
> However, I have already defined all the functions and it would be
> troublesome to change all of them to a new name.
>
> Any hint ?
> Thanks
>
> Paulo Gustavo Grahl, CFA
>

[Note to Paulo:I changed the code slightly: defining Nonfunctions
separately messed things up.]

Hi Paulo,

The following should do it.

test<-function(x)x^2
test2<-5
test3<-77
ls()

rm(list=ls()[
sapply(ls(),
function(x){
class(get(x))!="function"
})
])
ls()

Regards,

Gustaf

--
Gustaf Rydevik, M.Sci.
tel: +46(0)703 051 451
address:Essingetorget 40,112 66 Stockholm, SE
skype:gustaf_rydevik

[Duncan Murdoch]

On 02/02/2009 8:16 AM, Paulo Grahl wrote:
> Dear list members,
>
> Does anyone know how to use rm() to remove only variables but not
> declared functions from the environment ?
> I understand I could name all the functions with, let's say
> "f_something", make sure that all variables do not start with "f_" and
> then remove all BUT objects starting with "f_".
> However, I have already defined all the functions and it would be
> troublesome to change all of them to a new name.
>
> Any hint ?

Here's a list of functions: lsf.str()
And here's a list of everything: ls()
So here are non-functions: setdiff(ls(), lsf.str())
And here they go: rm(list = setdiff(ls(), lsf.str()) )

Duncan Murdoch

[Kenn Konstabel]

You can get a list of all functions in your workspace with

ls()[sapply(ls(), function(x) is.function(get(x)))]
# or ls()[sapply(sapply(ls(), get), is.function)]

Removing everything else is

rm(list=ls()[sapply(ls(), function(x) !is.function(get(x)))])
# or rm(list=ls()[!sapply(sapply(ls(), get), is.function)])
That suffices if you don't have any names starting with .period; if you do,
you'll need ls(all=TRUE)

KK

[[alternative HTML version deleted]]

[Paulo Grahl]

Thank you all for the prompt answer !!
It did solve my problem perfectly !
Rgds,
Paulo

[Greg Snow]

If you want to keep the functions, why not move them to a different environment so that they don't get deleted when you delete everything else (this will also work better if you want to use these same functions in other R sessions).

The most comprehensive way to do this is to create a package with the functions (package.skeleton will get you started).

One of the simplest ways to do this (if the package idea is overkill, though if you expand this, the package solution may not be overkill in the long run) is to use the 'save' command to save your functions into a file, delete everything including the functions, then use 'attach' to attach the file you saved the functions in. Now you can still use the functions (just be careful if you try to edit them), but they are not in the main environment where the data is stored and when you delete 'everything' the next time, the attached functions will not be affected.

Hope this helps,

--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg...@imail.org
801.408.8111

[Paulo Grahl]

Thanks Greg.
I did in the past looked into the details of how to create a package.
I did not seem too complicated, but it would be time consuming -- an
then when one thinks in creating a package (even for his own use) it
always a good idea to check for wrong inputs, to have all functions
well documented, etc. The functions I've developed so far are not yet
in this stage.

But i liked the idea of using attach(). I had overlooked this point in
the attach() description.
Thanks.

Paulo Gustavo Grahl, CFA

[Carl Witthoft]

Slightly related to this (I think Mr. Rydevik's code solved the question),
is a silly thing I wrote up one weekend. It started out as a clone of
the unix "rm -i" command, and kept on going out of control :-)

I'm not claiming this is clean, or the best way to do this, but it does
let you apply a wide variety of functions to your collection of 'items'

Carl

-------------
askrm<-function(items,fn="rm",ask=TRUE){
killed<-NA
thecall<-vector('list')
j<-1

for (thenam in c(items)){
if(ask==TRUE){
prmpt<-paste("Do ",fn," on ",thenam,"? ")
readline(prompt=prmpt)->theans
}
else theans="y"
if(theans=="y"){

#have to get to parent envir. to find the object of interest
#as.name() gets rid of quotes...
# paste() dumps all output into a single element of list
# Note that,e.g., str() returns nothing, just cats to screen.
eval(call(fn,as.name(thenam)),envir=parent.frame(1))->evout
paste(evout,collapse=" ")->thecall[j]
cat("the result is ", as.character(thecall[j]),'\n')
killed[j]<-thenam
j<-j+1
}

}
#keeping track of what happened
outs<-list(killed=killed, calls=thecall)
return(invisible(outs))